Opponents of a proposed transatlantic trade deal hope to draw tens of thousands onto German streets Saturday, on the eve of a visit by US President Barack Obama.

Obama’s trip — to open an industrial technology fair in the northern city of Hanover and hold talks with Chancellor Angela Merkel and other European leaders — was intended to lend momentum to flagging efforts to see the world’s biggest trade pact finalised this year.

But the Trans-Atlantic Trade and Investment Partnership (TTIP) has run into major opposition, not least in Europe’s top economy Germany, where its foes have raised the spectre of eroding ecological and labour market standards and condemned the secrecy shrouding the talks.

A loose coalition of trade unions, environmentalists and consumer protection groups will join the colourful march, where activists from the anti-globalisation organisation Attac say they will dress up as “hippie” Merkel and Obama characters, hoisting banners reading “Free Love Instead of Free Trade!”

“We are not demonstrating against Obama but against TTIP,” said the head of another campaign group, Campact, Christoph Bautz, who expected around 50,000 people to attend the rally in Hanover.

“TTIP is deeply un-American and anti-European because it endangers our shared value: democracy.”

A similar protest in October in Berlin drew up to 250,000 people, according to organisers, signalling an uphill battle for the deal’s passage.

“TTIP was never going to be an easy undertaking, but it is still a very important one if you are interested in seeing prosperity in Europe grow,” Merkel’s spokesman Steffen Seibert told reporters Friday.

“Our goal is to wrap up the negotiations this year and the chancellor will underline this in the talks with President Obama in Hanover.”

US Trade Representative Michael Froman told the German business daily Handelsblatt Friday that if the negotiators fall short, “there will be real doubts about whether we will ever get this agreement through”.

The Hanover meeting comes just before a 13th round of TTIP negotiations starting Monday in New York.

Froman insisted that a transatlantic free trade deal could provide useful glue to hold the EU together as “centrifugal forces” threaten to rip it apart.

“The refugee crisis, the danger of Britain leaving the EU, continuing concerns about Greece and the rise of right-wing populist parties in many countries — our hope is that TTIP can be a positive force and Europe can show that it can also stand together in difficult times,” he said.

But scepticism against those arguments is growing, not diminishing in Germany, and Economy Minister Sigmar Gabriel admitted this week: “It is possible that TTIP will fail.”

Just 17 percent of Germans say they support TTIP, according to a Bertelsmann Foundation poll of more than 3,000 people published Thursday, in free fall from the 55 percent registered two years ago.

During the same period, firm opposition to the pact rose to 33 percent from 25 percent.

The picture in the United States, where sentiment on trade deals has soured as a fractious presidential election season drags on, is hardly more promising.

The “yes” camp has shrunk to 15 percent from 53 percent, while nearly half — 46 percent — say they feel too ill-informed to form an opinion.

US Agriculture Secretary Tom Vilsack, the longest serving member of Obama’s cabinet, warned on a visit to Germany this month that the time was now to rally around the accord, also in the interest of global food security.

With a protectionist streak running through the presidential race from both major parties, Obama’s successor at the White House would likely be a less muscular backer of free trade.

Given the limited amount of political capital available to a “lame duck” president, analysts on both sides of the Atlantic said, the White House was more likely to aggressively pursue ratification of one of Obama’s signal achievements, the Trans-Pacific Partnership trade deal (TPP) with Asia, than to struggle to complete negotiations on TTIP.